Have you noticed the "On This Day" tidbits shown here and there on TolkienGuide and social media? At this time it has news items from prior years on this site, and also letters from the Letters Guide. Book milestones and other items will be coming soon as well.

https://www.tolkienguide.com/onthisday

There's a simple form box at the top of the page, so you can look at any day of the year, not just "today" - you can see what letters were sent on someone's birthday for example.